# Chai error: Is there support for moment.js date compare features?

**URL:** <https://community.postman.com/t/chai-error-is-there-support-for-moment-js-date-compare-features/13637>\
**Category:** Help Hub\
**Tags:** tests\
**Created:** [June 24, 2020, 12:29am UTC](https://community.postman.com/t/chai-error-is-there-support-for-moment-js-date-compare-features/13637 "2020-06-24T00:29:02Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![jshafer](https://sea2.discourse-cdn.com/getpostman/user_avatar/community.postman.com/jshafer/32/4810_2.png) [@jshafer](https://community.postman.com/u/jshafer)\
**Post date:** [June 24, 2020, 12:29am UTC](https://community.postman.com/t/chai-error-is-there-support-for-moment-js-date-compare-features/13637/1 "2020-06-24T00:29:02Z")

</div>

I am checking to see if a date that is returned via my request is the same or after a date that is stored in my collection variables. I would like to use moment.js to do this because it looks like a really clean way to get what I want – it has just the comparison I’m looking for: isSameOrAfter ([https://momentjs.com/docs/#/query/is-same-or-after/](https://momentjs.com/docs/#/query/is-same-or-after/)). However, when I attempt to use this, or even the more basic “isAfter”, I get “Error: Invalid Chai property: isAfter”.

As far as I can tell, this should be supported. Postman documentation ([https://learning.postman.com/docs/postman/scripts/postman-sandbox-api-reference/](https://learning.postman.com/docs/postman/scripts/postman-sandbox-api-reference/)) says it supports moment 2.22.2 and isAfter is tagged as moment 2.0.0. Am I reading this wrong?

I tried out a of couple of the other moment features, like .add and it worked fine. I finally winnowed my code down to a very basic test:

```
const moment = require("moment")
var jsonData = pm.response.json().results
//let updated_since = moment(jsonData.updatedAt).format("YYYY-MM-DD")
//let us_var = moment(pm.collectionVariables.get("updatedSince")).format("YYYY-MM-DD")

if(jsonData.length > 0) {
    (pm.test("Response data is filtered by updatedSince", () => {
        var size = jsonData.length
        for(var i = 0; i < size; i++) {
            pm.expect(moment("2020-06-06")).isAfter(moment("2020-05-20"))
        }
    },
    pm.environment.set("x-next-token", null)
))}

```

Still getting the Chai error with the above. I guess I’ll pursue ways outside of moment.js to do this, but I’m disappointed. Please let me know if there is something basic I’m missing here. I’m relatively new to coding.

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<div class="post-metadata">

**Author:** ![danny-dainton](https://sea2.discourse-cdn.com/getpostman/user_avatar/community.postman.com/danny-dainton/32/29401_2.png) [@danny-dainton](https://community.postman.com/u/danny-dainton)\
**Post date:** [June 24, 2020, 6:19am UTC](https://community.postman.com/t/chai-error-is-there-support-for-moment-js-date-compare-features/13637/2 "2020-06-24T06:19:24Z")

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Hey @jshafer

Welcome to the community!! ⭐

This looks like it’s to do with the way that you are writing your `pm.expect` statements.

The `moment` syntax that you’re using returns `true/false`, you can see this if you log the result to the console:

```
const moment = require("moment")

console.log(moment("2020-06-06").isAfter(moment("2020-05-20")))

```

In order to use this in a test, you would need to write the test like this:

```
pm.test('testing', () => {
    pm.expect(moment("2020-04-06").isAfter(moment("2020-05-20"))).to.be.true
}) 

```

This is putting the whole `moment` statement inside the `pm.expect()` function and then using the chained _getters_, write the assertion.

Just something to remember when using `chai` assertions, the first getter to start the chained assertion needs to be `.to` after the `pm.expect()` statement - For example `pm.expect(1).to.eql(1)`

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<div class="post-metadata">

**Author:** ![jshafer](https://sea2.discourse-cdn.com/getpostman/user_avatar/community.postman.com/jshafer/32/4810_2.png) [@jshafer](https://community.postman.com/u/jshafer)\
**Post date:** [June 24, 2020, 4:16pm UTC](https://community.postman.com/t/chai-error-is-there-support-for-moment-js-date-compare-features/13637/3 "2020-06-24T16:16:15Z")

</div>

Wonderful! That works. Thank you so much. Great tip on the .to after Chai assertions.